Ferroelectric properties of Cd1−xZnxTe solid solutions

Measurements of the spontaneous polarization P, x‐ray diffraction, birefringence, dielectric constant at different frequencies, and specific heat Cp of the Cd0.9Zn0.1Te alloy are presented. The results demonstrate that this system exhibits a diffuse, second‐order ferroelectric transition. The transition is of order‐disorder type as deduced from the dielectric measurements. It is found that: (a) The birefringence is proportional to P, as expected from a system with a piezoelectric paraelectric phase; (b) the heat capacity is given by Cp=(Tc/C)‖(PdP/dT)‖, where C is the Curie constant. One of the main phenomena observed in these solid solutions is the instability of the ferroelectric phase: Once the neighborhood of the transition temperature is reached, the transition disappears upon subsequent cooling. A hypothesis for this instability is offered in terms of a two‐state configuration‐coordinate diagram.